Exercise isn’t just for the young and spry. It’s also key for maintaining strength, balance and mental well-being in older folks — and it’s never too late to start.

Now four new studies presented at the Alzheimer’s Association International Conference in Vancouver add to the growing evidence that the elderly should get off the couch, showing that regular exercise — both aerobic training, like walking, and strength training involving weights — helps improve memory and reduces the frequency of those momentary hiccups we call “senior moments.”

In one study, Dr. Kirk Erickson of the University of Pittsburgh and his research team found that when sedentary adults start working out even after the age of 65, the brain still benefited, increasing in size and function. The researchers looked at 120 inactive adults, some of whom were cognitively healthy and some who reported having mild memory lapses. The volunteers were assigned to a yearlong exercise program, doing either moderate-intensity walking or participating in a stretching-toning program.

The researchers used an MRI to scan the brain and found that after a year of exercise, the walking group showed improved memory and increases in volume in the hippocampus, a brain region crucial for processing memory, compared with those who stretched.

“Our findings suggest that the aging brain remains modifiable, and that sedentary older adults can benefit from starting a moderate walking regimen,” Erickson said in a statement.

Two other studies looked at older adults who had already been diagnosed with mild cognitive impairment (MCI), a condition involving mild problems with thinking and memory that may precede dementia or Alzheimer’s. One of the studies, led by Dr. Hiroyuki Shimada of the National Center for Geriatrics & Gerontology in Japan, evaluated 47 adults ages 65 to 93 who were assigned to either a multifaceted exercise program or a no-exercise group for a year. The exercise program, which included aerobic exercise, strength training and balance training, involved two 90-minute sessions a week. Those who didn’t exercise attended health-education classes instead. At the end of the study, the exercise group showed improvements in memory and language skills.

In the second study, by researchers at the University of British Columbia in Vancouver, women ages 70 to 80 with MCI were assigned to one of three groups: resistance training, aerobic training or balance-and-tone training. In each program, participants exercised two times a week for six months. At the end of the study period, those who had participated in strength training fared best: they outperformed the other groups on tests measuring attention, memory and higher-order brain functions like conflict resolution. They also showed increased function in three brain regions involved in memory. The same results were not found for those doing aerobics, though that group did improve on a memory task.

“It’s definitely one of the first times resistance training has been looked at in connection with Alzheimer’s. And we’ve seen in that body of literature that people who do resistance training increase their ability to be more mobile, but it may have some other benefits,” Heather Snyder, of the Alzheimer’s Association, told CNN

For the final study, also by the University of British Columbia, researchers looked at 155 community-dwelling women ages 65 to 75 who were randomly assigned to do either resistance training or balance-and-tone training for a year. In this case, researchers found that both groups had improved memory at the end of the study, but the women who started out with higher levels of cognitive function at the beginning of the study reported more improvements in memory with resistance training.

“Where previously we had seen positive associations between aerobic activity, particularly walking, and cognitive health, these latest studies show that resistance training is emerging as particularly valuable for older adults,” said Dr. William Thies, chief medical and scientific officer of the Alzheimer’s Association, in a statement.

It not only improves mobility and strength, but as the recent research shows, it appears to boost brain function as well. One more reason to add weights to your workout.